1. Field of the Invention
The invention generally relates to a transverse conveying screw for a harvesting front attachment.
2. Related Technology
In the harvesting of crop materials using agricultural harvesting machines, as a rule the crop material is first lifted from the ground on the field (e.g. with the prongs of a pick-up) or alternatively is cut off (e.g. by the cutting members of a cutting apparatus or by mowing and intake apparatus in a “corn biter”, or by the intake and plucking mechanism of a “corn plucker”). The crop, or the parts thereof that are to be picked (e.g. ears of corn), is/are then conveyed transversely and delivered to the intake channel or inclined conveyor of the harvesting machine. In many harvesting front attachments, the transverse conveying is accomplished by a transverse conveying screw.
Typically, a transverse conveying screw is comprised of a circular cylindrical tube and spiral screw elements disposed around the periphery of the tube, the latter serve to convey the crop material. The spiral screw elements extend, in their spiral course, inward from the two respective sides and terminate in the central region of the transverse conveying screw, ahead of the intake channel of the harvester. The screw elements adjoin terminal discs, the peripheries of which are partially formed by a circular arc around the screw axis. Downstream of the circular arc, the radius of the terminal disc diminishes spirally, so as to sharply come to an end. Between the terminal discs, axially and radially extending conveying vanes extend, for conveying the crop materials rearward.
In other prior art transverse conveying screws, circular terminal discs that extend radially have been seen. Terminal discs of the prior art also have been provided with an incline, i.e. they extend in the axial direction of the transverse conveying screw. They successively narrow as they extend inwardly, and have a wave-shaped periphery.
The task performed by the transverse conveying screws is to deliver the crop material in a maximally uniform manner over the width of the intake channel, so that the harvesting machine is laterally loaded as uniformly as possible. This uniformity is particularly important in conventional thresher harvesters having straw vibrators, because more highly loaded vibrators generate greater losses than less highly loaded vibrators. Uniform feed over the width is also important in baling presses, for the sake of homogeneity of the bales.
The transverse conveying screws having terminal discs that extend generally radially take the crop material, which is conveyed by the screw elements to the terminal discs, and generally deliver it rearward. Any conveying elements disposed between the terminal discs essentially convey rearward only the crop material which is presented in the region of their lateral extent. As a result, the intake channel of the harvesting machine often will receive more crop material in its outer regions than its inner regions. Inclined terminal discs provide a certain lateral distribution of the crop material which it delivers, but its contribution is insubstantial, because of the relatively small dimensions of the terminal discs.
The underlying problem of the present invention was to devise a transverse conveying screw wherein the magnitude of the described problems is reduced.